论文部分内容阅读
林火是大兴安岭林区重要的干扰因子之一,揭示其发生的时空分布特征和规律,对林火安全管理和未来气候变化下的林火预测具有重要作用。本文以大兴安岭1967—2006年发生的林火为研究对象,将其视为一个在时间和空间上完全随机的点过程。采用时间点过程方法中的变异系数和阿伦因子及空间点格局分析中的Ripley K函数和Kernel空间密度函数等估算方法,分别对大兴安岭林火时间和空间分布的聚集性范围和尺度进行分析。结果表明:在较小的时间尺度上,林火分布趋向随机过程,随着观测时间长度增大,分布的聚集性表现越显著;空间分布上,林火在一定距离尺度内表现为聚集分布,超过该尺度则为随机泊松分布;林火的分布往往聚集在某些特定区域,存在明显的林火高发区。这些结果进一步揭示了大兴安岭林火时空的内在分布规律,但对于导致这些林火时空分布格局的机制还有待进一步研究。
Forest fire is one of the most important disturbance factors in Daxing’anling forest area. It reveals the spatial and temporal distribution characteristics and rules of forest fire and plays an important role in forest fire safety management and forest fire prediction in the future climate change. In this paper, the forest fire that occurred in Daxinanling from 1967 to 2006 was taken as a research object, which was regarded as a completely random point process in time and space. The range and scale of the distribution of time and space distribution of forest fire in Daxing’anling were analyzed by using the coefficient of variation in point-in-time process method, the Ripley K function in Arunan factor and spatial point pattern analysis, and Kernel spatial density function. The results showed that on a small time scale, the distribution of forest fire tended to be stochastic, and the distribution of aggregates was more pronounced with the increase of observation time. On the spatial distribution, the forest fire was aggregated and distributed within a certain distance scale, Stochastic Poisson distribution was beyond this scale. The distribution of forest fire often gathered in some specific areas, with obvious forest fire-prone areas. These results further revealed the inherent distribution of fire in the Greater Hinggan Mountains. However, the mechanism of the spatial and temporal distribution of forest fire remains to be further studied.